Alnus; hybrids; polymerase chain reaction; Phytophthora; sequence-characterized amplification region
Abstract :
[en] Isolates of alder Phytophthora were collected in the southern part of Belgium on riverbanks planted with Alnus glutinosa and A. incana. They were compared with strains isolated in other European countries in terms of maximum temperature for growth, oogonia shape, pathogenicity on Alnus seedlings and genetic traits. Using both molecular techniques [random amplified polymorphic DNA (RAPD) and random amplified microsatellite (RAMS)], two groups of isolates were identified, the first group being further divided into two subgroups, Ia and Ib, using RAPD. Most of the Walloon alder Phytophthora isolates as well as the standard type from UK (formally designated P. alni subsp. alni) fell into group Ia. One isolate was classified in group Ib with the German and Dutch variants (P. alni subsp. multiformis), while three isolates were placed with the Swedish variant (P. alni subsp. uniformis) in group II. In terms of morphological properties, isolates from groups Ia and Ib developed colonies with a felt-like appearance and usually produced numerous oogonia, varying from wavy to warty after 1 week (group Ia) or 2–3 weeks (Ib) in darkness. In contrast, colonies from group II isolates were generally irregular, and smooth oogonia were produced in low quantities after approximately 1 month in culture. A polymerase chain reaction (PCR) using sequence-characterized amplification region (SCAR) primers derived from a polymorphic amplification product generated with a RAPD primer was developed for the specific detection of alder Phytophthora. The specificity and sensitivity of this test are discussed here.
Brasier CM. The hybrid alder Phytophthoras: genetic status, pathogenicity, distribution and competitive survival. In: Gibbs J, van Dijk C, Webber J (eds), Phytophthora Disease of Alder in Europe, Edinburgh, UK, Forestry Commission, Bulletin, 2003, 126, pp. 39-54.
Brasier CM, Kirk SA. (2001) Comparative aggressiveness of standard and variant hybrid alder Phytophthoras, Phytophthora cambivora and other Phytophthora species on bark of Alnus, Quercus and other woody hosts. Plant Pathol 50:218-229.
Brasier CM, Rose J, Gibbs JN. (1995) An unusual Phytophthora associated with widespread alder mortality in Britain. Plant Pathol 44:999-1007.
Brasier CM, Cooke DEL, Duncan JM. (1999) Origin of a new Phytophthora pathogen through interspecific hybridization. Proc Natl Acad Sci USA 96:5878-5883.
Brasier CM, Kirk SA, Delcan J, Cooke DEL, Jung T, Man In't Veld WA. (2004) Phytophthora alni sp. nov. and its variants: designation of emerging heteroploid hybrid pathogens spreading on Alnus trees. Mycol Res 108:1172-1184.
Cavelier M, Claessens H, Etienne M. (1999) Premier signalement du Phytophthora de l'aulne (Alnus glutinosa) en Belgique. Parasitica 55:63-71.
Chowdappa P, Brayford D, Smith J, Flood J. (2003) Molecular discrimination of Phytophthora isolates on cocoa and their relationship with coconut, black pepper and bell pepper isolates based on rDNA repeat and AFLP fingerprints. Curr Sci 84:1235-1238.
Debruxelles N, De Merlier D, Dufays E. La maladie de l'aulne: que faire? Fiche d'information sur la maladie de l'aulne. Namur (Belgium), Ministère de la Région wallonne, DGRNE - Division de l'eau, 2003, 3 pp.
Delcan J, Brasier CM. (2001) Oospore viability and variation in zoospore and hyphal tip derivatives of the hybrid alder Phytophthora. Forest Pathol 31:65-83.
Ersek T, English JT, Schoelz JE. (1995) Creation of species hybrids of Phytophthora with modified host ranges by zoospore fusion. Phytopathology 85:1343-1347.
Erwin DC, Ribeiro OK. Isolation and detection of Phytophthora. In: Erwin DC, Ribeiro OK (eds), Phytophthora Diseases Worldwide, St Paul, Minnesota, USA, APS Press, 1996, pp. 8-41.
Gibbs JN. (1995) Phytophthora root disease of alder in Britain. EPPO Bull 25:661-664.
Gibbs JN, Strouts R, Rose J. Brasier CM. An Unusual Phytophthora associated with Disease of Common Alder. Report on Forest Research 1994. London, HMSO, 1994, pp. 27-28.
Goodwin SB, Fry WE. (1994) Genetic analysis of interspecific hybrids between Phytophthora infestans and Phytophthora mirabilis. Exp Mycol 18:20-32.
Hantula J, Lilja A, Parikka P. (1997) Genetic variation and host specificity of Phytophthora cactorum isolated in Europe. Mycol Res 101:565-572.
Lilja A, Rikala R, Hietala A, Heinon R. (1996) Stem lesions on Betula pendula in Finnish nurseries and the pathogenicity of Phytophthora cactorum. Eur J Plant Pathol 26:89-96.
Man In't Veld WA, Veenbaas W-R, Ilieva E, de Cock AWAM, Bonants PJM, Pieters R. (1998) Natural hybrids of Phytophthora nicotianae and Phytophthora cactorum demonstrated by isozyme analysis and random amplified polymorphic DNA. Phytopathology 88:922-929.
Nagy ZA, Bakonyi J, Ersek T. (2003) Standard and Swedish variant types of the hybrid alder Phytophthora attacking alder in Hungary. Pest Manag Sci 59:484-492.
Pavlicek A, Hrda S, Flegr J. (1999) FreeTree - Freeware program for construction of phylogenetic trees on the basis of distance data and bootstrap/jacknife analysis of the tree robustness. Application in the RAPD analysis of the genus Frenkelia. Folia Biol (Praha) 45:97-99.
Schubert R, Bahnweg G, Nechwatal J et al. (1999) Detection and quantification of Phytophthora species which are associated with root-rot diseases in European deciduous forests by species-specific polymerase chain reaction. Eur J Plant Pathol 29:169-188.
Shaner G, Finney RE. (1977) The effect of nitrogen fertilization on the expression of slow-mildewing resistance in Knox wheat. Phytopathology 67:1051-1056.
Streito JC. A review of diebacks and declines of alder (Alnus spp.) in Europe. In: Gibbs J, van Dijk C, Webber J (eds), Phytophthora Disease of Alder in Europe, Edinburgh, UK, Forestry Commission, Bulletin, 2003, 126, pp. 15-24.
Streito JC, Jarnouen de Villartay G, Tabary F. (2002) Methods for isolating the alder Phytophthora. Forest Pathol 32:193-196.
Werres S, Marwitz R, Poerschke U, Themann K. (2001) A long-term study of Phytophthora species in Germany: 2. Phytophthora species which could not be definitely identified. J Plant Dis Prot 108:121-135.
White TJ, Bruns T, Lee S, Taylor J. Amplification and Direct Sequencing of Fungal Ribosomal RNA Genes for Phylogenetics. In: Innis MA, Gelfand DH, Sninsky JJ, White TJ (eds), PCR Protocols, a Guide to Methods and Applications, San Diego, USA, Academic Press, 1990, pp. 315-322.
